State-mandated testing in Maryland has detected elevated lead levels in drinking fountains and taps in schools in Montgomery County, Anne Arundel County and Harford County.

A bill passed last year by the state legislature and signed by Gov. Larry Hogan (R) requires that public and private schools test for lead in drinking water outlets. That testing, the first phase of which had to be completed by July 1, yielded levels of lead above the Environmental Protection Agency guideline of 20 parts per billion (ppb) in water fixtures in several school districts.

There is no safe level of lead in blood for children, according to the Centers for Disease Control and Prevention. The metal is especially harmful to young children, whose brains and nervous systems are still developing, and elevated levels can lead to behavioral problems, learning disabilities and other lifelong ill effects.

In Montgomery County — the state’s largest school district — 238 of the 13,248 fixtures tested were found to have lead levels above 20 ppb. Those fixtures were taken off line, and the district “implemented remediation measures,” according to its website. Students won’t have access to those fixtures again until they show lead levels below 20 ppb.

“Any of the samples coming back above the acceptable level of 20 ppb is concerning and alarming and necessitates further evaluation,” said Travis Gayles, chief of public health services for Montgomery County. Gayles, a pediatrician, said it would be difficult to determine just how much lead a child drinking from one of the affected spigots received, and what the effect might have been.

“It’s tricky to know how often a particular child was exposed to a particular source, how long,” he said. “And it’s tricky to really assess the effect of intermittent exposure to a particular source.”

Laura Stewart, a PTA leader in Montgomery, said she’s hoping school officials will adopt a more stringent standard for taking action — rather than 20 ppb, she would like to see 5 ppb trigger an intervention to ensure children aren’t exposed.

Another parent, Rebecca Morley, testified to the Montgomery County Board of Education this summer after receiving a letter notifying her that the water at her child’s elementary school had been tested and was safe. Citing a recent U.S. Government Accountability Office report, she asked the county to adopt a threshold of no more than 5 ppb, with a goal of lowering it if possible.

At an appearance Thursday in Baltimore, Democratic gubernatorial candidate Ben Jealous said the state needs to be more aggressive in preventing lead exposure.

Jealous — flanked by a Montgomery County public school teacher and a nurse represented by SEIU Local 1199, which has endorsed Jealous for governor — said the state was allowing children to “be the canaries in the coal mine on the issue of lead poisoning.”

“We don’t act until there’s 10 [micrograms] in their bloodstream. Other states say five. Doctors will tell you the only safe number is zero,” said Jealous, a former head of the NAACP who is challenging Hogan in November.

The District and 18 states use the CDC’s recommendation of requiring action when the lead levels in children’s blood reaches 5 micrograms per deciliter.

Jealous said that, if elected, he also would push for $5 million for more lead inspectors for the state Department of the Environment and a $1,500-per-unit tax credit for property owners who need to remove sources of lead from residences, modeled after a similar program in Massachusetts.

“It’s a small price to pay for a big improvement in the safety of young people,” he said.

Hogan has pushed through his own initiatives to tackle childhood lead exposure in the state. In 2015, for example, Hogan’s administration announced it would begin requiring blood tests for lead for all children at 12 and 24 months of age, not just for those at high risk of lead poisoning.

A spokeswoman for Hogan said the governor has supported adopting the CDC’s recommended 5 micrograms, but added that ­doing so would require an act of the legislature.

“It’s great to see Ben Jealous follow the governor’s lead in pushing for the adoption of the CDC’s standards,” Hogan spokeswoman Amelia Chassé wrote in an email, adding that legislation last year to change the standard, which Hogan supported, did not pass the General Assembly. “Doing a little homework before making ill-informed and unsubstantiated attacks is usually a good idea.”

Meanwhile, officials at districts where elevated lead was detected in drinking water said they were working on the problem.

Derek Turner, a spokesman for the Montgomery County Public Schools, said fixtures that had results over 20 ppb were taken out of service to be fixed.

A number of the water sources tested that had high lead levels were not accessible to children, or had been dormant, which may be why the lead levels were elevated, he said. Some hadn’t been used in two years, he said, “so when we tested them the lead levels were through the roof.”

Officials are discussing which threshold makes sense “to make sure our kids’ drinking water is safe,” he said.

He also encouraged parents to check their fixtures at home. “It’s not just a school issue, but a community issue,” Turner said.

Montgomery County Council member Marc Elrich (D-At Large) said he is drafting legislation to require schools to take action if a water fixture shows lead levels of more than 5 ppb — matching the requirement at D.C. schools.

Elrich, who is the Democratic nominee for Montgomery County executive, said that would be just a first step to address the lead problem, noting that children also can be exposed to lead in water fixtures at day care, recreation centers and homes.

“Nobody wants lead in the water of any fountain kids are exposed to, whether you’re the government or a private provider,” said Elrich, adding that he wanted to study the cost of installing ­water filters at schools.

Anne Arundel County Public Schools has gotten results back for 23 of the 33 schools and found 30 sources of drinking water with lead levels testing at 20 ppb or higher. Ten were at High Point Elementary School in Pasadena.

Those outlets were shut off within 24 hours of getting results, said Bob Mosier, a spokesman for the district, which is replacing the fixtures. The water will be tested again, and access will not be restored until lead levels drop to acceptable levels, he said, as officials work to find the source of the problem.

“We have been trying to move as swiftly as possible,” Mosier said.

At Prince George’s Public Schools, which has a standard of 10 ppb, spokesman John White said all drinking water sources in the schools were tested by the end of January. “If drinking water tested above 10 ppb, the school system attempted to remediate the problem, replacing old fixtures, for example, and retested,” he said. If water still tested high, those drinking water sources were turned off and capped, White said.

The system has begun installing filtered water fountains in all 207 schools, work that will be completed this school year, he said.

Most experts agree that 20 ppb is not a stringent enough threshold, said Marc Edwards, a professor of civil and environmental engineering at Virginia Tech who is nationally known for his battles with government agencies for safer water in places such as the District and Flint, Mich. A national standard is badly needed, he said. “It creates this very unfortunate contentious debate all over the country: How safe do we want our schools to be?”

While Edwards said research shows “lower and lower levels of lead are more harmful than we thought,” he and colleagues recently wrote a paper cautioning against unrealistic standards.

“If you’re going to go with 1 [ppb], you probably just want to go with bottled water,” he said. “Our filters, our existing plumbing systems just aren’t set up yet to be below 1 all the time.”

He said the D.C. Public Schools’ standard of 5 ppb is a reasonable solution and could be a national model.

“When it comes to lead in schools, no news is bad news,” Edwards said, adding that testing for and detecting lead is key to preventing future harm. “If you’re not hearing about this problem, that’s when you should be worried.”